Entropy generation of nanofluid flow in a microchannel heat sink

Manay, Eyüphan; Akyürek, Eda Feyza; Şahin, Bayram

doi:10.1016/j.rinp.2018.03.013

Cited by 75 publications

(21 citation statements)

References 28 publications

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“…It is the ratio of the entropy generation number for the nanofluid to the base fluid under the same geometrical configuration. This ratio can be lower or higher than 1, depending on the efficiency of the system when operating on nanofluid 63 . Thus, S n is used to measure the thermodynamic impact of the nanofluid in the MCHS and a lower than unity value implies that the irreversibility in the MCHS when using nanofluids is much lower than when using the base fluid (water).…”

Section: Microchannel Entropy Generationmentioning

confidence: 99%

Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger

et al. 2020

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In this study, an interrupted microchannel heat sink with rib turbulators was studied for its thermohydraulic effectiveness and entropy generation in a compact space. The rib edges are modified to enhance the overall functioning of the system by reducing the pressure drop. The working fluid used was Al2O3‐water nanofluid, and increasing the Reynolds number and nanoparticle concentration triggered a reduction in the heat sink's maximum temperature. These also offer a decrease in resistance to heat transfer, and there is an improvement in the evenness of the temperature of the interrupted microchannel heat sink, as regions with the likelihood of hot spot reduced drastically. At Re = 100, increasing the nanoparticle concentration from 0% to 4% enhanced the heat transfer coefficient by 38.41% for the interrupted microchannel heat sink‐base (IMCH‐B) configuration. Under similar conditions, the convective heat transfer coefficient for the interrupted microchannel heat sink‐fillet (IMCH‐F) increased by 43.69%. Furthermore, at 0.5% concentration, changing the Reynolds number from 100 to 700 augmented the heat transfer coefficient by 70.65%. Thus, the maximum temperature of the substrate's bottom surface was reduced by 53.83°C when the system was operated at Re = 700 and nanoparticle concentration of 4%. The IMCH‐C also showed relatively close results at all observed volume fractions. For the IMCH‐C, the maximum temperature of the bottom surface was reduced by 41.98°C at Re = 700 when compared with Re = 100% and 4% concentration. Although at high Reynolds numbers and concentrations, the pressure drops are higher, the performance enhancement criteria prove that the nanofluid is superior to water and the edge modifications show significant performance improvement. More importantly, the IMCH‐F heat sink showed the optimum performance based on the performance evaluation criteria at Re = 300 and φ=2% (ie, at this point, the heat transfer coefficient is maximum and the pressure drop is minimum). On the other hand, the optimal thermodynamic performance was observed at Re = 700 and φ=4%. The numerical results demonstrated a potential way to exploit nano‐suspensions for thermal applications, especially for high‐energy flux systems with compact space constraints.

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Section: Microchannel Entropy Generationmentioning

confidence: 99%

Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger

et al. 2020

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“…The HT to the NF from the MC walls was increased by increasing φ as well as Hartmann number. Manay et al (2018) performed experiments to investigate the effect of different φ on the EG in TiO 2 -water NF flow through the MCHS. The EG in the MCs with different channel heights under the laminar and steady flow and CWHF boundary condition was investigated.…”

Section: Eg In Mcs With Nanofluidsmentioning

confidence: 99%

Entropy generation analysis due to heat transfer and nanofluid flow through microchannels: a review

Kumar

Bharj

2020

IJEX

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This work presents a detailed review of the entropy generation due to the heat transfer and the fluid flow through different channels. The earlier contribution of the researchers in the form of theoretical, numerical and experimental studies on the entropy generation in the conventional or microchannels, with or without disruption in the flow and with or without the use of nanofluids is reviewed. The brief discussion on the microchannels, disrupted microchannels, nanofluids and entropy generation is presented. Studies performed on the channel cross-sectional shapes and rib shapes for thermal performance optimisation are discussed in the paper. Nanoparticles such as Al2O3, Cu, CuO, Ag, SiO2, etc. have been used for preparing the nanofluids along with water, ethylene glycol, etc. as base fluids. Additionally, the effect of disruption in flow field on the entropy generation is also discussed. The disruptions in the form of ribs, cavities, vortex generators, etc. have been taken into account. It is hoped that this review article can provide a basis for further research on the irreversibility analysis of the nanofluid flowing through disrupted microchannels to improve the hydrodynamic and thermal performance of the system.

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“…The increment in Re of nanofluid flow in the MCHS resulted in the increase in the frictional EGR [24,25]. Rastogi and Mahulikar [26] performed optimization of a circular microtube configuration using EG minimization and the optimum diameter is obtained corresponding to the minimum total EGR change, i. e., where the optimum channel diameter decreases with decreasing channel length.…”

Section: Introductionmentioning

confidence: 99%

Circular Microchannel Heat Sink Optimization Using Entropy Generation Minimization Method

Kumar

Bharj

2020

Journal of Non-Equilibrium Thermodynamics

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The performance of the microchannel heat sink (MCHS) in electronic applications needs to be optimized corresponding to the number of channels (N). In this study optimization of the number of channels corresponding to the diameter of the microchannel ({D_{N}}) using an entropy generation minimization approach is achieved for the MCHS used in electronic applications. The numerical study is performed for constant total heat flow rate ({\dot{q}_{tot}}) and total mass flow rate ({\dot{m}_{tot}}). The results indicate that the dominance of frictional entropy generation ({S_{gen,Fr}}) increases with the reduction in diameter. However, the entropy generation due to heat transfer ({S_{gen,HT}}) decreases with the reduction in diameter. Therefore, the optimum diameter ({D^{\ast }}) is calculated corresponding to the minimum total entropy generation ({S_{gen,total}}) for the optimum number of channels ({N^{\ast }}). Furthermore, the entropy generation number ({N_{S}}) and Bejan number (Be) are also calculated.

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Entropy generation of nanofluid flow in a microchannel heat sink

Cited by 75 publications

References 28 publications

Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger

Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger

Entropy generation analysis due to heat transfer and nanofluid flow through microchannels: a review

Circular Microchannel Heat Sink Optimization Using Entropy Generation Minimization Method

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Entropy generation of nanofluid flow in a microchannel heat sink

Cited by 75 publications

References 28 publications

Thermohydraulic and entropy characteristics of Al2O3‐water nanofluid in a ribbed interrupted microchannel heat exchanger

Thermohydraulic and entropy characteristics of Al2O3‐water nanofluid in a ribbed interrupted microchannel heat exchanger

Entropy generation analysis due to heat transfer and nanofluid flow through microchannels: a review

Circular Microchannel Heat Sink Optimization Using Entropy Generation Minimization Method

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Product

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Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger

Thermohydraulic and entropy characteristics of Al₂O₃‐water nanofluid in a ribbed interrupted microchannel heat exchanger